Is OpenGL function loader needed?

Issue

On desktop OSes, OpenGL function loaders like GLEW, GLAD, etc. are used to load functions at runtime. But what about on Android? How are functions loaded? I've looked at a few apps and all of them seem to depend on EGL and GLES. But AFAIK EGL isn't a loading library, but an interface. Well, an interface to an interface as GLES is actually an interface.

This leads to another question: How come Android uses EGL when it is generally not used on desktops?

Solution

Back when I used android a bit, you could either link to the GLES 2.0 library, or you could link to the GLES 3.0 library, so kinda as if they provide the function pointers for you. ish. If you used GLES3.0, but the phone you ran it on only supported 2.0, your app would not load. To work around this, I always linked to GLES 2.0, and wrote my own function loader using eglGetProcAddress to extract the GLES3.0 API if available. This is pretty much how function loaders on windows/linux work (using wglGetProcAddress or glxGetProcAddress).

GLES has always been a stripped down version of the full blown desktop GL. It has always targeted a smaller subset of the full blown API (removing all of the legacy cruft), which in turn simplifies the OpenGL driver code somewhat, which in turn should reduce memory usage and save a little bit of battery life. Basically it's just more suited to use on a low power system where battery life is a concern.

Answered By - robthebloke